This invention relates to a dialyser cartridge of roll type particularly for extracorporal artificial kidneys.
Dialyser cartridges of plate type are presently known, comprising a first and second support layer facing each other and extending in a plane. Between said first and second layer a dialyser membrane is disposed, through which the blood to be dialysed is passed. In these known types, projections in the form of square-based pyramidal elements are uniformly distributed over the facing surfaces of the first and second support layer. The purpose of the projections or projecting elements is to assist uniform distribution of the dialysing liquid which is passed in contact with the outer surface of the dialysing membrane for achieving dialysis of the blood.
Dialyser cartridges of roll type were subsequently introduced, in which the membrane support layers are spirally wound and contained in an outer casing generally of cylindrical shape. The use of support layers with square-based pyramidal elements disposed specularly one to the other has not however been possible in cartridges of roll type, because the facing pyramidal elements of two wound layers inevitably become mutually embedded, with consequent obstruction of the passage zone for the dialysing liquid. To obviate this disadvantage various designs have been introduced, in which the facing surfaces of the two support layers in dialyser cartridges of roll type have been formed and shaped in various ways. Although having given satisfactory results, the designs adopted have however not always proved able to give that uniformity of distribution of the dialysing liquid which is obtainable with flat support layers comprising projections in the form of square-based pyramids.